page 1 hfp workshop, rami session, 2-4 mar 2009k,ucla why is reliability, availability,...

HFP Workshop, RAMI Session, 2-4 Mar 2009k,UCLA

Why Is Reliability, Availability, Maintainability, and Inspectability Important to the Future of Fusion?

Why Is Reliability, Availability, Maintainability, and Inspectability Important to the Future of Fusion?

L. WaganerConsultant for The Boeing Company

Harnessing Fusion Power Workshop2-4 March 2009

University of California-Los Angeles


Greenwald Theme -Harnessing Fusion Power

The state of knowledge must be sufficient to design and build, with high confidence, robust and reliable systems which can convert fusion products to useful forms of energy in a reactor environment, including a self-sufficient supply of tritium fuel.

Specifically for Reliability, Availability and Maintainability

Demonstrate the productive capacity of fusion power and validate economic assumptions about plant operations by rivaling other electrical energy production technologies.


The End Goal For Fusion - Produce Competitive Electrical Power

Our immediate goals are how to:

1) assess our current technology maturity,

2) determine our gaps, and

3) postulate research thrusts to close the gaps

This will enable Demo to validate that the ultimate goal can be achieved with acceptable risk


How Can RAMI Help?

The busbar cost of electricity is the most important factor for an electrical generating power plant.

The plant must be an affordable, reliable, maintainable energy source and all of these factors are contained in the cost of electricity: COE = [CAC + (CO&M + CSCR + CF) * (1 + y)Y+ CD&D , where

(8760*PE* Pf)

CAC is the annual capital cost charge (total capital cost x Fixed Charge Rate)CO&M is the annual operations and maintenance costCSCR is the annual scheduled component replacement costCF is the annual fuel costsy is the annual escalation rate (0.0 for constant dollar and y for current dollar)Y is the construction and startup period in yearsPE is the net electrical power (MWe)Pf is the plant capacity factor (~ plant availability)CD&D is the annual decontamination and decommissioning converted to mills/kWhr

Major Effect

Minor Effect (salaries, equip)

Minor Effect (cost, life)


Plant Availability is High Leverage Tool - Equivalent in Importance to Power Production -

• Operational Time is the power production time over a set period of time.

• Scheduled Down Time is the sum of regularly scheduled maintenance periods for the power core, other reactor plant equipment, and balance of plant equipment - Related to component lifetimes, replacement schedules, and MTTR

• The Unscheduled Down Time is the summation of maintenance times to repair unexpected operational failures that cause the plant to cease power production – Determined by MTTR/MTBF of all critical components

Availability = Operational Time

Operational Time + Scheduled Down Time + Unscheduled Down Time


Availability is Determined by:

1. Reliability – The inherent reliability of all the power core and plant component parts to achieve a very high system reliability, (> 0.99). This means that individual components are validated to achieve extremely high levels of reliability.

2. Maintainability – The ability to rapidly and reliably maintain all the plant parts, especially the remote maintenance of the power core, is absolutely essential. Power core maintenance may be highly automated and likely autonomous in 50 years.

3. Inspectability - An examination of plant components to determine if there are any indications that components might fail in service, any reduction or increase in performance and/or service lifetime. This implies extensive pre- and post-operational examinations, along with an embedded, real-time monitoring of all operational components as a part of an integrated plant health management system that will predict and schedule preventative maintenance actions (new technology).


Vision of Power Core Maintenance ITER and other DT experimental facilities have, or will

have, provided a wealth of remote handling experience that will be applicable to CTF, Demo, and the Commercial Power Plant

However, those machines were never designed to have rapid remote maintenance to achieve very high levels of availability

Conceptual fusion power plant studies have postulated two general approaches that have some promise (and a lot of difficulties) to achieve the required availability goal.

A. Remove large blanket and divertor modules with articulated arms and installed rails through several large maintenance ports

B. Remove complete sectors containing blankets, divertors, and hot shield/structure between TF coils and radially out through large vacuum maintenance ports.


A. Modular Maintenance Approach

• Simultaneous maintenance in 3 ports

• Module size limited to several tonnes

• Fixed Transfer Chambers control contamination and enhance times

• Mobile Transporters transfer used and new components to/from Hot Cell

• Main Port is used for removing blanket and divertor modules

• ECH launcher/waveguide removed

• ECH port can then be used as Auxiliary maintenance port


Removal of Blanket Modules• Plumbing would be

disconnected from inside the plumbing pipes

• A mobile Extractor machine would enter the maintenance port and disconnect the mechanical attachments

• Modules would be extracted from core and returned to Hot Cell

• The above actions repeated for all modules

• New or refurbished modules would be reinstalled and tested in-situ (repeated actions)


• Requires a higher degree of integration between power core elements, power core building, and maintenance approach

• Simplifies coolant and mechanical connections outside of hot shield

• Allows simpler power core maintenance, but more massive elements to be moved with precision

B. Sector Maintenance Approach

• More fluid and structural connections pre-tested in hot cell rather than inside power core


Example of AT Sector Replacement

BasicOperationalConfiguration

Withdrawal of Power Core Sector with Limited Life Components

Cross Section Showing Maintenance Approach Plan View Showing the Removable Section Being Withdrawn


Sector Removal

Remote equipment is designed to remove shields and port doors, enter port enclosure, disconnect all coolant and mechanical connections, connect auxiliary cooling to the sector, and remove power core sector


Operational Configuration

•Bioshield (2.6-m-thick) is incorporated into building inner wall

•Building wall radius determined by transporter length + clear area access

•Extra space provided at airlock to assure that docked cask does not limit movement of other casks


Power Core Removal Sequence

•Cask contains debris and dust•Vacuum vessel door removed and transported to hot cell

•Core sector replaced with refurbished sector from hot cell

•Vacuum vessel door reinstalled

•Multiple casks and transporters can be used

•Multiple locations can be accessed simultaneously


Shutdown and Start-up Times Must Be Minimized

Shutdown TimelineMaintenance Action Duration of Serial

Operations, h Duration of

Parallel Operations, h

Shutdown and preparation for maintenance Cooldown of systems, afterheat decay 24 De-energize coils, keep cryogenic 2.0 Pressurize power core with inert gas 2.0 Drain coolants, fill with inert gas 6.0 Subtotal for shutdown and preparation 30

Maintenance Action Duration of Serial Operations, h

Duration of Parallel

Operations, h Startup tasks Move transporters and casks to hot cell 0.8 Evacuate core interior 10.0 Initiate trace or helium heating 10.0 Fill power core coolants 8.0 Bake out (clean) power core chamber 12.0 Checkout and power up systems 4.0 12.0 Subtotal for startup 34.0

Startup Timeline

Dominated by cooldown of systems and core

Assumes streamlined processes for core evacuation, bakeout, and coolant fills

= 2.6 days


Estimated Repetitive Maintenance Times for Replacement of a Single Power Core Sector

•Assumes a single cask and transporter

•Defines major maintenance activities

•Assumes all removal and replacement activities are remote and automated

•Repetitive actions require less than 1.5 days

Maintenance Action Duration ofSerial

Operations, h

Duration ofParallel

Operations, hRepetitive maintenance tasksMove cask to port and dock to port 1.0Open cask door and raise port isolation door 0.2Disengage vacuum vessel door 3.6 Move transporter forward to engage vacuum door 0.2 Remove weld around vacuum door 2.0 Disconnect VS coil electrical and I&C connections 0.2 Disconnect vacuum door water coolant connections 1.0 Disengage door to prepare for removal 0.2Remove vacuum vessel door into cask 1.0Lower isolation and transporter doors and undock cask 0.2Move to hot cell, unload vacuum door, return, and dock 2.5Open cask door and raise port isolation door 0.2Disengage power core sector 3.2 Move transporter forward to engage power core sector 0.2 Disconnect I&C connections 0.2 Disconnect five coax LiPb coolant connections 2.0 Disengage mechanical supports 0.6 Disengage sector to prepare for removal 0.2Remove power core sector into cask 1.0Lower isolation and transporter doors and undock cask 0.2Move to hot cell, unload sector, load new sector, return, and dock 3.0Open cask door and raise port isolation door 0.2Move power core sector from cask into near-final core position 1.0Install power core sector 7.7 Align sector and finalize position 1.0 Engage mechanical supports 1.0 Connect five coax LiPb coolant connections 5.0 Connect I&C connections 0.5 Disengage transporter and move back inside cask 0.2Lower isolation and transporter doors and undock cask 0.2Move to hot cell, load vacuum door, return, and dock 2.5Open cask door and raise port isolation door 0.2Move vacuum door from cask into near-final position 1.0Install vacuum door 5.7 Align vacuum door and finalize position 1.0 Prep, weld, and inspect door perimeter 3.0 Connect door water coolant connections 1.0 Connect VS coil and I&C connections 0.5 Disengage transporter and move back inside cask 0.2Lower isolation and transporter doors and undock cask 0.2Subtotal for repetitive tasks 34.8


Maintenance Times for Replacing Different Number of Sectors at a Time

Note: Blankets, Divertors, and other In-Vessel Components are designed for a 4 full power year (FPY) lifetime

Number ofSectors

Replaced

Shutdownand Startup

Time, h

Time to ReplaceSectors, h

MaintenanceAction

Duration, h

MaintenanceActions OverFour FPYs, h

Availabilityfor ScheduledCore Outages

EquivalentDays/Year

4 64 139.2 203.2 812.8 0.9773 8.475 64 174 238 748.8 0.9791 7.806 64 208.8 272.8 Incl. in Above - -8 64 278.4 342.4 684.8 0.9808 7.13

16 64 556.8 620.8 620.8 0.9826 6.47

One Cask and One Transporter


Multiple Sets of Casks and Transporters Can Improve Times

•At least two sets should be used (4.23 equivalent d/y)•Availability improvements by larger numbers of casks and transporters probably would not justify added cost

• Spare maintenance equipment will be provided

Equivalent Annual Maintenance Times for Multiple Sets

1 2 4 8 164 8.47 5.57 4.12 3.39 3.03

5 & 6 7.80 4.90 3.45 2.73 2.368 7.13 4.23* 2.78 2.06 1.7016 6.47 3.57 2.12 1.39 1.03

No. of Sectors

Replaced

Number of Maintenance Casks and Transporters


Need to Establish Fusion Power Plant Availability Goals Consistent

with Energy Community• All reasonably new electricity-generating plants are now

operating in the 85-90% class• In 25-40 years, state-of-the-art plant availabilities will be 90+% • Fusion Power Plant (FPP) needs get to 90% or better

Representative Plant Systems Availability Goals


What Should Be Demo’s Availability Goal?

This notional graph illustrates how Availabilities have to grow through ITER, CTF, and DEMO

0

50

1001950 2000 2050 2100

Projection of Electric Plant Availability

ITER Operation

CTF Operation?

Demo Operation?

FPP Operation?

1950 2000 2050 2100

Now


Summary• Achieving RAMI goals are imperative to the success

of fusion producing competitive power

• Designs shown are merely ideas at this point to help point the way to an integrated power plant design

• Power core elements must be highly reliable and robust through simulation and test

• Efficient maintenance of the power core is highly design dependent

• High availabilities must be demonstrated by CTF and Demo

• Demo must look like and act like the first commercial power plant


Recommendations• An integrated power core, maintenance system, and

building design is essential to help select subsystem options for Demo and the Fusion Power Plant (FPP)

• Pre-cursor facilities and thrusts must mature and validate subsystems and maintenance systems that are a part of an integrated design approach leading to Demo and ultimately to the FPP

• An Integrated Plant Health Management system is necessary to predict and schedule preventative maintenance actions


Questions?

page 1 hfp workshop, rami session, 2-4 mar 2009k,ucla why is reliability, availability,...

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